Tikka I believe is the only one in that caliber that I am aware of. According to there brochure, Tikka T3
, the .260 is available in LH on the T3 Hunter and T3 Lite. It appears to be an option so it most likely will have to be ordered.
7mm-08 and .243 is available quite easily by other makers but the .260 is hard to come by as I am sure you are aware.